1. Field of the Invention
The present invention is generally related to the control of a marine vessel and, more particularly, to the acceleration control used during the initial launch to bring a water skier from a generally stationary position to a water skiing position.
2. Description of the Related Art
Those skilled in the art of marine propulsion systems, particularly in relation to water ski boats, are familiar with various techniques and procedures used to facilitate the initiation, or launch, of a water skiing effort. In addition, those skilled in the art of marine propulsion systems are familiar with various types of engine speed control systems, including the operation of throttle handles and procedures for transmitting information relating to the position of a throttle handle to an engine control system that selects the operating speed of the engine.
U.S. Pat. No. 5,074,810, which issued to Hobbs et al. on Dec. 24, 1991, describes an automatic speed control system for boats. An apparatus for accurately maintaining the speed of a motorboat at a value set by an operator is described. The speed of the boat is measured and compared to a desired speed set by the operator and the speed of the boat engine is adjusted to minimize the difference between the desired speed and the actual speed. The device further incorporates features allowing the incremental adjustment of the desired speed, storage of several of these speeds for future use, and a safety feature causing the system to behave as though it were of a conventional manual type if the operator makes a gross change to the setting of a manual throttle lever.
U.S. Pat. No. 5,110,310, which issued to Hobbs on May 5, 1992, describes an automatic speed control system for boats. An improved apparatus for accurately maintaining the speed of a motor boat at a value set by an operator is described. Speed of the boat and force on the boat due to a water skier are measured. Actual speed is compared to a desired speed set by the operator and the speed of the boat engine is adjusted to minimize the difference between the desired speed and the actual speed. Engine speed is further adjusted to prevent or minimize changes in the speed of the boat caused by the forces on the boat due to a water skier. The device further incorporates features to induce the likelihood of speed measurement errors due to malfunctioning speed measuring devices.
U.S. Pat. No. 5,586,535, which issued to Syomura on Dec. 24, 1996, describes an engine rotational number controller. It includes an engine rotational number detector for detecting the number of rotations of an engine, a throttle opening detector for detecting a throttle opening of the engine, an ignition device, a stepping motor, an injector, and a control circuit for delaying an ignition timing of the ignition device when the number of rotations of the engine becomes higher than a predetermined upper limit in the case where the throttle number is constant and for opening a sub-throttle valve of a throttle valve by means of the stepping motor to increase an amount of intake air and to increase an amount of injected fuel in the injector when the number of rotations of the engine become lower than a predetermined lower limit in the case where the throttle opening is constant.
U.S. Pat. No. 5,700,171, which issued to Horton on Dec. 23, 1997, describes a speed control system. A speed controller for a vehicle comprises speed sensors which output to a controller which in turn outputs to a servo motor. The servo is connected to the inner cable of a coaxial cable, the outer sheath of which is lodged between a buttress and the engine throttle. The distance between the buttress and engine throttle lever is, at least when the throttle is closed, shorter than the length of the outer sheath such that the outer sheath obtains a curved configuration. The inner cable extends beyond the engine throttle lever to a support. Accordingly, when the controller operates the servo to draw in the inner cable, the outer sheath is urged to straighten and therefore push against the engine throttle lever to open it. Conversely, when the inner cable is paid out, the outer sheath is relaxed to allow the engine throttle lever to close.
U.S. Pat. No. 5,765,528, which issued to Kamimaru on Jun. 16, 1998, describes an idle speed control system for an automotive internal combustion engine. During idling of an internal combustion engine, when there is a difference between an actual engine speed and a target idle speed which is preset in accordance with an engine load, the opening and closing timings of an intake/exhaust vaIve of the engine is changed in accordance with the difference between the actual engine speed and the target idle speed to change an intake airflow sucked into the engine.
U.S. Pat. No. 6,109,986, which issued to Gaynor et al. on Aug. 29, 2000, discloses an idle speed control system for a marine propulsion system. The system controls the amount of fuel injected into the combustion chamber of an engine cylinder as a function of the error between a selected target speed and an actual speed. The speed can be engine speed measured in revolutions per minute or, alternatively, it can be both speeds measured in nautical miles per hour or kilometers per hour. By comparing target speed to actual speed, the control system selects an appropriate pulse width length for the injection of fuel into the combustion chamber and regulates the speed by increasing or decreasing the pulse width.
U.S. Pat. No. 6,414,607, which issued to Gonring et al. on Jul. 2, 2002, discloses a throttle position sensor with improved redundancy and high resolution. The sensor is provided with a plurality of sensing elements which allow the throttle position sensor to provide a high resolution output to measure the physical position of a manually movable member, such as a throttle handle, more accurately than would otherwise be possible. The plurality of sensors significantly increases the redundancy of the sensor and allows its operation even if one of the sensing elements is disabled.
U.S. Pat. No. 6,485,341, which issued to Lanyi et al. on Nov. 26, 2002, discloses a method for controlling the average speed of a vehicle. The average speed of a vehicle is controlled over a predetermined time period, or indefinitely, or distance length is described with reference to selecting a desired average speed, measuring an actual speed, and maintaining a cumulative error determined as a function of the difference between the average speed and actual speed and the time over which the actual speed measurement was taken. Based on the cumulative total of speed-time error, a compensatory speed is calculated that will reduce the cumulative speed-time error to an acceptable tolerance range within a selected period of elapsed time. Although particularly applicable to competition situations in which an average speed is dictated for use over a particular competition course, the average speed controlling method can be used in other situations where the average speed of a vehicle must be controlled.
U.S. Pat. No. 6,672,282, which issued to Harrison et al. on Jan. 6, 2004, describes an increased resolution electronic throttle control apparatus and method. The device is intended for controlling a throttle of an electric throttle control equipped engine including providing a throttle position feedback signal as a function of integer counts, each of the counts representing a resolution of a predetermined angle of actual throttle position, providing a desired throttle position command as a set point value being a function of half counts and generating an error signal representing a difference between the desired throttle position command value and the throttle position feedback signal value. A relay output signal is generated in response to the error signal, the relay output signal having one or two values depending upon a sign of the error signal and a direction of change of the error signal. A throttle actuator command is then generated as a function of the relay output signal value having a half count resolution.
U.S. patent application Ser. No. 11/245,370 (M09953) which was filed by Ehlers et al. on Oct. 6, 2005, discloses an acceleration control system for a marine vessel. The system is provided which allows the operator of a marine vessel to select an acceleration profile to control the engine speed of a marine vessel from an initial starting speed to a final desired speed. When used in conjunction with tow sports, such as wakeboarding and water skiing, the use of an acceleration profile provides consistent performance during the period of the time when a water skier is accelerated from a stationary position to a full speed condition.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
In situations where the acceleration profile, over a preselected period of time, of a marine vessel is important in facilitating the launch procedure of a water skier, it would be significantly beneficial if a preferred acceleration profile could be learned by a control system of a marine vessel and then repeated upon demand to consistently accelerate that skier in a manner that is unchanged over a repeated number of launchings.